Devices for cleaning the walls of bore holes



April 2, 1957 A. E. ATKINSON DEVICES FOR CLEANING THE WALLS OF BORE HOLES Filed OCT.. 14, QR

5 Sheets-Shea?l l April 2, 1957 A. E. ATKINSON DEVICES FOR CLEANING THE WALLS OF BORE HOLES Filed 0G13. 14, 1953 3 Sheets-Sheet 2 April 2, 1957 A. E. ATKINSON 2,787,328

DEVICES FOR CLEANING THE WALLS OF BOR'E HOLES I Filed on. 14, 195: e sheets-sheet s DEVICES FOR CLEANING THE WALLS OF BRE HOLES Albert Edward Atkinson, Esher, England Application October 14, 1953, Serial No. 386,015

Claims priority, application Great Britain September 18, 1953 This invention relates to devices sometimes known as scratchers for cleaning the Walls of bore holes of the kind comprising a plurality of spring fingers or wires carried by an annular or other structure which is adapted to be mounted on the outside of the bore hole casing, the fingers extending outwardly from the said structure or ring and being arranged so that by reciprocating or rotating the easing in the hole the fingers exert a scratching action for cleaning the wall by the removal of caked mud or the like therefrom. Such devices are primarily intended for removing caked mud from the bore hole immediately before the casing is cemented in the hole. The main object of the invention is to provide an improved form of spring finger for devices of the above type which can be conveniently formed or set to the desired shape without affecting their resilience, i. e. the ability of the finger to return to its initial position 'after it has been defiected during the cleaning operation.

The invention consists in a spring finger in or for a. device of the kind described comprising a closely coiled helix of resilient wire or like material having one or more rigid inserts or cores.

The invention also comprises a spring finger according to the precedingparagraph having a plurality of spaced inserts or cores corresponding to positions at which the finger is initially shaped or set, the flexibility or resilience of the finger being afforded at positions corresponding to the spaces between the inserts or cores.

The invention also comprises a spring finger element formed to a narrow U-shape to afford a pair of fingers when mounted upon the annular or other structure of the cleaning device.

in the accompanying drawings,

Figure 1 is a plan view of a cleaning device for bore holes constructed in accordance with the invention;

Figure 2 is a side elevation of the device of Figure 1 with certain of the spring fingers omitted for clarity;

Figure 3 is a sectional elevation of one of the spring finger elements before shaping;

Figure 4 is a side elevation of a shaped spring linger element;

Figure 5 is a view of the element of Figure 4 viewed in the direction of the arrow A;

Figure 6 is an elevation of a modified form of structure for carrying the spring fingers;

Figure 7 is a side view of the y'arrangement of Figure 6; and

Figs. 8 and 9 are similar elevation and side views of another modification.

In carrying the invention into effect according -to one convenient mode, there is provided a bore hole cleaning device including an annular structure or ring comprising connected arcuate elements as described in the specification of patent application Serial No. 290,055, now Patent No. 2,714,424. These arcuate elements 1 and 2 are formed from sheet 4material to a semi-circular shape and the two longitudinal edges of the element 2 are bent outwardly and over to form a fold portion 3 lying parallel rates arent ice tions of the fold portions 3. When the elements 1 and 2 are assembled as shown, the separated portions 6 of the folds 4 are displaced inwardly by pressing or hammering so that the ring halves are secured against relative longitudinal displacement. The spring fingers indicated generally at 8 comprise finger elements which are initially given a U shape as shown in Figure 3. These finger elements are secured to the outside of the annular structure composed of the elements 1, 2 by means of cleats or fastening plates 9. Each of sai-d cleats is formed with a U-shaped recess 10 to receive the correspondingly shaped end of the finger element, and includes a flange portion 11 which is shaped to lie against the outer surface of the annular structure xand is attached thereto by any suitable means, preferably by welding.

Figure 3 shows one of the spring finger elements before it is shaped to its final form. The element comprises a closely coiled helix of resilient wire 12, comprising or having the characteristics of steel piano wire, which is bent to a narrow Ushape. Before bending, mild steel inserts or cores 13, 14 Iand 15 are introduced into the helix to occupy the positions shown. These inserts preferably comprise round mild steel rod or wire of a diameter to fit closely within the helix. The end inserts 15 conveniently comprise mild steel nails, the heads 16 of which abut the open ends of the helix. After the inserts have been appropriately positioned in a straight length of the helix, this is bent at x to the form shown in Figure 3, and subsequently at the points y and z as shown in Figures 4 and 5 to provide the desired final shape. It will be seen that the inserts or cores are provided at the points of bending and afford means whereby the shaping of the helix to the required curves can be satisfac torily ensured and whereby the fingers are permanently set or maintained in the desired shape. Thus the bend x 'affords a U-shape to the inner end of the finger whereby it may be conveniently mounted on the device as later described. The bends y in the finger provide the necessary outward splaying of the fingers whereby they are adapted to effect the desired scraping action in the bore hole. After bending in the manner described, the finger elements are secured to the annular structure by the cleats or fastening plates 9 Aas previously described. lt will be seen that when formed as above the fingers S extend outwardly with respect to the central axis of the device or the casing on which it is adapted to be mounted and are also uniformly inclined to said axis, the extremities of the fingers extending substantially parallel with the aforesaid axis. It will be seen that the flexibility or resilience of the finger is afforded by the spaces between the inserts or cores.

Instead of mounting the fingers on an annular structure as previously described, they can be attached to metal strips which extend parallel to the axis of the casing and are secured thereto in spaced relation in a well known manner. With such arrangement, cleaning is effected by rotation of the casing. Mountings of this kind are shown in Figures 6 and 7, and in Figs. 8 and 9. The strips 17 are of channel section and side portions 18 can be welded to the casing. As shown in Figures 6 and 7, the spring fingers 8 are attached by means of cleats or fastening plates 9a, similar to those of the previous example, to the outside surface of the strip 17. As shown in Figures 8 and 9, the fastening plates 9a are the device can be employed. Also the invention is not restricted to the particular construction of 'annular or other structures described above. Also rings of solid, hinged or other types could be employed, one example being shown in the specification of British Patent No. 668,350.

By this invention there is provided an improved spring finger construction for devices of the kind described which affords sufficient stiffness for the service required combined with improved resilience in the sense of the ability of the fingers to return to their original position after they have been deflected during the cleaning operation. It is an important advantage of the invention that the bending or setting of the fingers to the desired shape during manufacture does not affect their flexibility or ability to return as indicated above.

I claim:

l. A device of the kind described comprising carrier means adapted to be mounted on the outside of a bore hole casing, spring fingers attached to the carrier means in circumferentially spaced relation thereto and shaped to project outwardly from said carrier means in a direction inclined to the axis of the said casing and also inclined with respect to the casing periphery whereby they are adapted to exert a scratching action on the wall of the bore hole upon movement of said casing therein, each of said fingers comprising a closely coiled helix of resilient wire such as steel piano wire having at least one angle or bend in the projecting portion thereof, and a rigid insert or core having a diameter to fit closely within the intern-al diameter of the spring finger so as to 2. A device according to claim l, in which each finger is provided with two or more spaced inserts or cores, the flexibility or resilience of the linger being afforded at positions corresponding to the spaces between the inserts or cores. l

3. A device according to claim 1, in which `a pair of fingers are constituted by a single length of closely coiled Wire helix having a generally U-formation, the U-shaped end of said formation being attached to the carrier means and the other ends of said formation constituting the projecting fingers.

4. A device according to claim l, in which each insert or core comprises a steel rod.

5. A device according to claim 1, in which a pair of fingers are constituted by a single length of closely coiled wire helix having a generally U-formation, and further comprising a cover plate shaped to receive said U-shaped end, and means for securing said cover plate to the carrier means to attach the fingers lto the latter, the other ends of the said U-shaped formation constituting the projecting fingers.

6. A device according to claim 1, in which each finger is attached to the carrier means at one end theerof, and each finger is provided with at least two spaced inserts in the projecting part thereof, one of said inserts being positioned at the end of the finger remote from its end of attachment.

7. A device according to claim 1, in which a pair of fingers are constituted by a single length of closely coiled wire helix having a generally U-formation, the U-shaped end of said formation being attached to the carrier means and having a correspondingly shaped rigid insert therein.

References Cited in the file of this patent UNITED STATES PATENTS 2,552,382 Roof May s, 1951 2,630,590 OBrien Mar. 1o, 1953 FOREIGN PATENTS 438,694 Great Britain Nov. 21, 1935 

